Level 3 UiDemo Walkthrough



Hi There,

Having a hard time in following the UiDemo Walkthrough from Level 3. Not sure why i am getting the below error when i do a test. Attaching the files, would be glad if someone can look and help on this.


UiPath_REFrameWork_UiDemo.zip (655.0 KB)

Rammohan B.



From the screenshot, looks like you were running the workflow from _Test.xaml file which contains a couple of invokes to other workflow files, the arguments have no values passed on to them and that’s the reason you are seeing the NullReferenceException.

Please try running it from Main.xaml file unless you were testing the invoked files, then pass the argument values.


Thanks for the Reply @PD2,
Yes, I have been testing the workflow from _Test.xaml file. I have been invoking 2 Workflow from this file i.e. InitAllSettings.xaml & InitAllApplications.xaml.

Look like as you mentioned i missed to pass in_Config Dictionary arguments for both the invoked workflows. However i am again stuck at the next step.

InitAllApplications.xaml workflow has an Open Application activity where i am passing the filename. When i pass the file as the actual path of my file then all seems to be working fine, however when i pass the filename as ‘in_Config(“UiDemoPath”).ToString’ as mentioned under the guide, i am again getting an error which states as below:

“Invoke workflow file: Open application ‘UIDemo (1).exe UiDemo’ : The system cannot find the file specified. (Exception from HRESULT: 0x80070002)”

I don’t see any problem with the path under orchestrator. Not sure why its not taking it.

Rammohan B.


Can you please check the config file for the path and see if it has the “(1)” In the Uidemo path. Looks like there is a mismatch


Ok, So I figured out the issue with the path now. However there is another issue related to passing of arguments between 2 invoked workflows.

I have 2 workflows under my _Test.xaml which invokes ‘InitAllSettings.xaml’ & ‘InitAllApplications.xaml’ workflows. I am storing ‘in_Config’ from ‘InitAllSettings.xaml’ & storing it under a local variable ‘Config’. So till here all looks fine.

Then I am passing the same Config variable to an in argument of ‘InitAllApplication.xaml’ workflow, however looks like no data is passed to the another workflow.

Due to no data being passed from the Config dictionary variable to the 2nd workflow, i am not able to pass the filepath to my ‘Open Application’ activity.

Rammohan B.


Hi Ram,
if you have completed UiDemo and Calculate security Credential Is it possible for you to can you please share them both with me